Cross-sensitivity in a child with anticonvulsant hypersensitivity syndrome

We describe a fulminant picture of anticonvulsant hypersensitivity syndrome (AHS) and the possible role of nitrazepam. A 5-month-old boy developed fever and rash after the use of phenobarbitone. Allergy to phenobarbitone was suspected. Nitrazepam was substituted for seizure control. Over the next few days he progressively collapsed with fever, facial oedema and multi-organ involvement. The diagnosis of AHS was delayed because nitrazepam has not been implicated in the development of cross-sensitivity. AHS is a severe multi-organ reaction to aromatic anti-epileptic drugs. It has been thought to occur as a consequence of pre-existing pharmacogenetic and immunologic abnormalities. Careful selection of anti-epileptic drugs is essential as cross-sensitivity is common. Intermittent benzodiazepines have been recommended in managing breakthrough seizures in AHS. However, the structure of benzodiazepines contains aromatic rings and potential cross-reactivity cannot be totally ignored. Although we do not have direct proof, we believe that nitrazepam prolonged the clinical course.